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Chapter 7.3 and 7.4 Cell Transport

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Presentation on theme: "Chapter 7.3 and 7.4 Cell Transport"— Presentation transcript:

1 Chapter 7.3 and 7.4 Cell Transport
Chapter 7.3 and 7.4 Cell Transport

2 Chapter Mystery?

3 Chapter 4 Vocab Active transport-transport across the cell membrane that requires energy Passive transport-movement across the cell membrane that does not require energy. Concentration gradient-difference of concentration across a space Osmosis Diffusion 6. Facilitated Diffusion 7. Aquaporin 8. Endocytosis 9. Exocytosis 10.receptor protein- a protein on the cell membrane that receives a signal molecule. 11. Hypertonic 12. Hypotonic 13. Isotonic

4 Main Function of the Cell Membrane
Membranes are selectively permeable so they control what moves in and out of the cell Based on size and polarity

5 The Cell Membrane

6 The Phospholipid bilayer
Every single cell exists in a liquid environment Bilayer made of phospholipids Hydrophilic Heads-love water (polar) Hydrophobic tails- hate water (non polar)

7 What are polar and nonpolar molecules?

8 So what moves in and out? Size Polarity In Out Small molecules
Non-polar and some small polar molecules Out Large molecules Polar

9 Passive Transport: Requires NO Energy
Every cell exists in a liquid environment. Every cell must maintain homeostasis Cells must regulate transport across the cell membrane

10 Concentration Gradients: the differences in concentration across a space.

11 Equilibrium B. equal concentrations across a space.

12 Diffusion: the movement from an area of high concentration to an area of low concentration.
1) a difference in concentration exists across the cell membrane 2) diffusion occurs down the gradient.

13 Cell membrane is selectively permeable
A. repels non polar molecules and ions. B. polar molecules and very small molecules can diffuse across the cell membrane.

14 Ion Channel: a polar pore through which ions can pass into a cell.
A. some molecules cannot pass directly through the cell membrane. B. Ion channels- allows polar molecules, (like ions) pass into the cell.

15 Facilitated Diffusion: Sugars and amino acids
                                                A. carrier proteins -bind to substances outside the cell and carry it inside. B. Amino acids and Sugars C. Down the concentration gradient. D. NO ENERGY REQUIRED

16 Osmosis: the diffusion of water through a selectively permeable membrane.
A. uses a concentration gradient B. passive transport C. Aquaporins-water channel proteins D. This is a type of facilitated diffusion


18 Hypertonic solutions 2. Water moves out of the cell-causes cell to shrink, called a Hypertonic solution

19 Hypotonic Solutions 3. Water moves into the cell-causes cell to swell and burst, called a hypotonic solution

20 Isotonic solutions 4. No net movement- cell remains the same, called a Isotonic solution.


22 How to Deal with osmotic pressure?
A. contractile vacuole-a water pump found in paramecium B. cell walls- keeps central vacuole from over expanding. Large organisms cells are bathed in blood or isotonic solutions

23 Review Questions 1. What is a concentration gradient?
2. Describe the movement of molecules during diffusion. 3. Can polar molecules pass through the cell membrane? Why or why not? What is a aquaporin? 5. What is the difference between a hypotonic, hypertonic and an isotonic solution. 6. What is passive transport?

24 Label the following cells as Isotonic, hypotonic, or hypertonic
Image from

25 Active Transport: Requires ATP
A Requires ATP 1. Carrier proteins-act as pumps 2. Against the concentration gradient. B. Sodium-Potassium Pump 1. Sodium ions-more on outside of cell 2. Potassium ions- more on inside of cell

26 How do you get Big Molecules across the cell membrane?

27 Answer: Endocytosis and Exocytosis

28 Endocytosis: too large to pass through the cell membrane.
A. polysaccharides and proteins B. use a vesicle C. cell forms a pouch around the substance. D. phagocytosis-engulfing prey.

29 Endocytosis

30 Exocytosis

31 Exocytosis A. the movement out of the cell using a vesicle.
B. the vesicle fuses with the cell membrane. C. golgi body-proteins modified here are released from the cell using exocytosis

32 Review Question 7. What is active transport?
8. How does a sodium-potassium pump work? 9. What are the similarities and differences between endocytosis and exocytosis? 10. What is the function of a receptor protein?

33 How do multicellular organism maintain homeostasis?
Cell specialization- in order for cells to be effective, they must work together. Teamwork

34 Levels of Organization in multicellular organisms

35 Levels of Organization
Cells- group of ORGANELLES working together to perform a particular function. Tissue- a group of cells working together to perform a particular function. Organ- a group of tissues working together to perform a particular function. Organ system- a group of organs working together to perform a particular function. Organism- all organ systems working together to maintain homeostasis

36 How do you send a text message to a cell?

37 Answer: Membrane Receptor Proteins Receive Information
1. Cells release signal molecules that carry info (hormones). 2. Receptor proteins-binds to specific receptor molecules 3. They can speed up or slow down cell activities.

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